This application claims benefit of Japanese Patent Application No. 11-331627 and 2000-72857 filed on Nov. 22, 1999 and Mar. 15, 2000, respectively, the contents of which are incorporated by the reference.
The present invention relates to a multiple display apparatus for displaying a single image on a screen by projecting a plurality of images thereonto and, more particularly, to a seamless multiple display apparatus, in which adjacent areas of a plurality of images projected onto a screen are overlapped.
FIG. 13 is a schematic view showing a general construction example of a rear projection type seamless multiple display apparatus.
The illustrated seamless multiple display apparatus in FIG. 13 has a plurality of (i.e., total number of 9=3xc3x973, 3 in horizontal (or X) direction and 3 in vertical (or Y) direction) liquid crystal projectors 10a to 10i disposed on the rear side of the screen 20. A single image is formed by images projected from the projectors 10a to 10i onto corresponding areas 20a to 20i on the screen 20.
In this seamless multiple display screen, an overlap part 21 is formed in adjacent parts of the images projected from the projectors 10a to 10i onto the screen 20. A problem is thus posed in that the display in the overlap part 21 is brighter than in the other areas because of the incidence of the light fluxes from two to four projectors. Another problem that may be encountered is a failure of projection of accurate image on the screen 20 due to such distortion as percussions without accurate position relationship among the projectors 10a to 10i. 
To prevent the above problems, Japanese Patent Laid-Open No. 9-326981 proposes a method, in which an image is previously projected onto a screen by using a test signal and photographed with a digital camera, photograph data thus obtained is then corrected, and geometrical conversion, color correction and luminance correction of an input signal are performed by using the corrected data.
The photographing by the digital camera is usually performed from the front of the screen. Therefore, a problem is posed that, watching the projected image in a direction deviated from the screen front (for instance in an oblique direction of an upward or downward direction), results in brightness difference in,the overlap part from the other areas of the screen due to different directions of projection of the projectors and visual field angle characteristic of the screen, so that the display in the overlap part is pronounced. More specifically, as shown in FIG. 14, when observing image projected from the projectors 10u and 10v onto the screen, the light doses at points A and B are equal in the case of observation in front-ward direction D1, but observation in oblique direction D2 results in that the point A is darker due to less light dose thereat than at the point B.
As shown, the prior art seamless multiple display apparatus has a problem that the display in an overlap part of adjacent images is pronounced.
The present invention was made in view of the above problems, and it has an object of providing a multiple display apparatus featuring superior display quality without pronounced display in any overlap part.
According to an aspect of the present invention, there is provided a multiple display apparatus for displaying an image with projection of a plurality of images from a plurality of image projecting means onto a screen, wherein: the plurality of image projecting means are disposed such that their images are projected substantially from one point onto the screen.
According to another aspect of the present invention, there is provided a multiple display apparatus for displaying an image with projection of a plurality of images from a plurality of image projecting means onto a screen, and the plurality of image projecting means are disposed such that their images are projected substantially from one point onto the screen and adjacent areas of images projected from the plurality of image projecting means onto the screen overlap one another.
According to other aspect of the present invention, there is provided a multiple display apparatus for displaying an image with projection of a plurality of images from a plurality of image projecting means onto a screen, wherein: the plurality of image projecting means are disposed such that their images are projected substantially from one point onto the screen and the image projecting means include image emitting means for emitting light fluxes of images to be projected onto the screen and reflecting means for reflecting the projection light fluxes emitted from the image emitting means toward the screen.
According to still other aspect of the present invention, there is provided a multiple display apparatus for displaying an image with projection of a plurality of images from a plurality of image projecting means onto a screen, and the plurality of image projecting means are disposed such that their images are projected substantially from one point onto the screen, adjacent areas of images projected from the plurality of image projecting means onto the screen overlap one another and the image projecting means include image emitting means for emitting light fluxes of images to be projected onto the screen and reflecting means for reflecting the projection light fluxes emitted from the image emitting means toward the screen.
Those of the plurality of image projecting means for projecting images onto the screen in the same row in horizontal direction are disposed horizontally, whereby images of light fluxes emitted from horizontally arranged predetermined image emitting means are projected via the reflecting means onto the screen in a predetermined area of the same row in horizontal direction; and those of the plurality of image projecting means for projecting images onto the screen in the same column in vertical direction are disposed vertically, whereby images of light fluxes emitted from vertically arranged predetermined image emitting means are projected via the reflecting means onto the screen in a predetermined area of the same column in vertical direction.
Those of the plurality of image projecting means for projecting images onto the screen in the same row in horizontal direction are disposed vertically, whereby images of light fluxes emitted from vertically arranged predetermined image emitting means are projected via the reflecting means onto the screen in a predetermined area of the same row in horizontal direction; and those of the plurality of image projecting means for projecting images onto the screen in the same column in vertical direction are disposed-vertically, whereby images of light fluxes emitted from vertically arranged predetermined image emitting means are projected via the reflecting means onto the screen in a predetermined area of the same column in vertical direction.
An area of the reflecting means of an image projecting means, on which the light flux projected from an adjacent image projecting means onto the screen is partly incident, is constructed such as to transmit part of the incident light.
According to further aspect of the present invention, there is provided a multiple display apparatus for displaying an image with projection of a plurality of images from a plurality of image projecting means onto a screen, wherein: the plurality of image projecting means are disposed such that their images are projected substantially from one point onto the screen, the plurality of image projecting means each include an image generating means for generating an image to be projected onto the screen, and a lens provided between the image generating means and the screen and those of the plurality of image projecting means, which do not regularly face the screen, are constructed such that the image surfaces of their image generating means are tiltable in vertical direction with respect to the lens axis.
According to still further aspect of the present invention, there is provided a multiple display apparatus for displaying an image with projection of a plurality of images from a plurality of image projecting means onto a screen, and the plurality of image projecting means are disposed such that their images are projected substantially from one point onto the screen and adjacent areas of images projected from the plurality of image projecting means onto the screen overlap one another, wherein: the plurality of image projecting means each include an image generating means for generating an image to be projected onto the screen, and a lens provided between the image generating means and the screen, and those of the plurality of image projecting means, which do not regularly face the screen, are constructed such that the image surfaces of their image generating means are tiltable in vertical direction with respect to the lens axis.
In the focus adjustment of the images projected from the image projecting means onto the screen by adjusting the tilting angles of the image surfaces, no image is projected from the image projecting means adjacent to the image projecting means under adjustment onto the screen.
The multiple display apparatus further comprises: detecting means for detecting a spatial frequency from an image obtained by photographing the image projected onto the screen; a computing means for obtaining the tilting angle of the image surface of the image generating means on the basis of the detection result by the detecting means; and a tilting control means for causing tilting of the image surface of the image generating means on the basis of the tilting angle obtained by in the computing means.
According to other aspect of the present invention, there is provided a multiple display apparatus for displaying an image with projection of images from a plurality of image projecting means onto a screen, wherein: a light dose limiting means for limiting the light dose in an overlap area of the images projected from the plurality of image projecting means onto the screen, is provided between the image projecting means and the screen.
The light dose limiting means has areas, in which transmitted light dose increases gradually from a point to another.
Other objects and features will be clarified from the following description with reference to attached drawings.